malloc vs calloc in Linux

results

$ ./test 
size     malloc + for    malloc+memset   calloc
2045     0.003761        0.002064        0.002071
2046     0.003695        0.002043        0.002039
2047     0.003695        0.002036        0.002044
2048     0.003704        0.002038        0.002036
2049     0.003734        0.002039        0.002069
2050     0.004025        0.004864        0.000002
2051     0.003986        0.004832        0.000002
2052     0.004025        0.004823        0.000002
2053     0.004050        0.004851        0.000002
2054     0.004030        0.004852        0.000001
2055     0.004003        0.004889        0.000002

test.cpp

#include <stdio.h>
#include <malloc.h>
#include <string.h>
#include <sys/time.h>

struct timeval tod;

void start()
{
    gettimeofday(&tod, NULL);
}

double stop()
{
    struct timeval now;
    gettimeofday(&now, NULL);
    double  secs = now.tv_sec  - tod.tv_sec ;
    double usecs = now.tv_usec - tod.tv_usec;
    return secs + (double)usecs/1e6;
}

int main(int argc, char **argv)
{
    printf("size\t malloc + for\t malloc+memset\t calloc\n");
    for (int i = 2045; i <= 2055; i++) {
        double mftime = 0, mmtime = 0, catime = 0;

        for (int iter = 0; iter < 100; iter++) {
            start();
            double *foo = (double *)malloc(i * i * sizeof(double));
            for (int k = 0; k < i * i; k++) foo[k]  = 0;
            mftime += stop();
            free(foo);
        }

        for (int iter = 0; iter < 100; iter++) {
            start();
            double *bar = (double *)malloc(i * i * sizeof(double));
            memset(bar, 0, i * i * sizeof(double));
            mmtime += stop();
            free(bar);
        }

        for (int iter = 0; iter < 100; iter++) {
            start();
            double *baz = (double *)calloc(i * i, sizeof(double));
            catime += stop();
            free(baz);
        }

        printf("%d\t %lf\t %lf\t %lf\n", i, mftime/100, mmtime/100, catime/100);
    }
    return 0;
}